346 DESOEIPTIVE GEOLOGY. 



overlying strata of limestone. But ascending the canon, the beds are found, 

 without showing any distinct break, to dip with an ever-diminishing angle 

 to the eastward, and soon beds, evidently conformable with the first 

 observed, can be traced continuously along the canon- wall, curving upward 

 and westward from a dip of over 60° east in the canon-bottom, to an 

 almost horizontal position high up on the spurs, and at times even with a 

 slight inclination westward. There is here, therefore, a sharp S-shaped 

 fold, the lower half of which is concealed beneath the surface, while the 

 western front of the upper half has been broken down in a fault. The low- 

 est beds exposed are a body of white granular quartzite, of a slight greenish 

 tinge, about 800 feet thick, with greenish clay-slates, both above and below, 

 the latter darker in color and more regular in cleavage. These beds rep- 

 resent the Ogden Devonian, as is determined by their position immediately 

 below the large body of Wahsatch limestone, and the finding of a Spirifer 

 centronatus and an undetermined JEiiomphalus, in some limestones in the 

 western foot-hills which, from their position, must have been faulted down 

 from the limestones immediately overlying these slates and quartzites. The 

 Spirifer centronatus is elsewhere in the range found in beds of the Waverly 

 period, but associated also with Spirifer alha-pinensis, which is also found in 

 well-recognized beds of the Devonian age at White Pine, Nevada. This 

 faulted portion, only seen in isolated pieces, consists of beds of light-colored 

 quartzite, overlaid by limestones having a steep dip westward. 



Eock Canon proper only exposes a section of the western shoulder 

 of the main ridge, already mentioned as characteristic of this portion of the 

 range, which here is much more developed than farther north at Timpanogos 

 Peak. Above the Ogden Quartzite are found a series of blue and gray 

 limestones, in general rather thinly bedded, sometimes semicrystalline in 

 texture, with occasional thin beds of quartzite. About 1,000 feet higher in 

 the series, an undetermined Spirifer was obtained, which may probably be 

 Sub-Carboniferous. In the various limestones, in general rather more 

 heavily bedded, between this and the head of the canon, where it opens 

 out into the longitudinal depression at the foot of the main high ridge, 

 which corresponds with the line of fault already mentioned in the western 

 face of Timpanogos, are found only fossils belonging to the Coal-Measures, 

 such as Spirifer opimus and Productus punctatus. Those which could be 



